1. Field of the Invention
The invention relates to an orthopedic device, especially ortheses or prostheses having components that are mounted so as to be pivotable with respect to one another.
2. Description of Related Art
Orthopedic devices having two components that are articulated and mounted so as to be pivotable with respect to one another are equipped with sensors and actuators for specific applications. Based on the acquired sensor data, changes can be made to the orthopedic device. For example, the damping properties of a joint can be changed as a function of the acquired sensor data. Likewise, it is possible to initiate movement-assisting measures via actuators or equip the orthopedic device just with sensors, whose sensor signals, e.g. can be wirelessly transmitted to a receiver. This makes it possible for the prostheses user in question to monitor or check the device during use so that any adjustments that may need to be made can be done more easily.
Generally, the sensors or actuators or transmission devices are supplied with electrical power from a battery, which ensures uninterrupted operation over a set time period. This period comprises the typical active period during a day, whereas the battery is charged during an inactive period. The batteries that can be used for operation of the orthopedic devices are limited both in their dimensions and in their weight because in orthopedic devices the components that are used need to be as small and lightweight as possible. This results in a limited charging capacity of the battery. Therefore, is problematic to provide additional sensors or actuators or to provide effective assistance of a movement using minimal equipment. The operating times are also limited.
U.S. Pat. No. 5,703,474 describes converting mechanical force to electric power and to thereby charge a battery. Using the ground reaction force produced by the weight of a person while he/she runs to generate piezoelectric energy is also known. In the IEEE-MICRO issue of May-June 2001, pages 30-42, a piezoelectric arrangement is described that is applied to a flexible sheet on a shoe sole. The generated power is used to illuminate the shoe soles. The electrical power that can be generated by using the piezoelectric element on a flexible sheet is minimal and therefore not suitable for use in an orthopedic device.